<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<style>
    button {
        margin: auto auto;
    }
</style>
<body>
    <button>这是一个会触发弹窗的按钮</button>
    <script>
        let buttonClass = document.querySelector('button')
        buttonClass.addEventListener('click',function(){
            alert('我被弹出来了！！！！')
        })
    </script>
</body>
</html>